1. Field of the Invention
This invention relates to a system and to a method for multiple compositing, within a virtual environment, of an image frame or image sequence of a puppet character, with an image frame or image sequence of a real/action image of the same or another puppet; and to a method for multiple compositing of such real/action images.
2. Description of the Prior Art
Puppet shows have existed since antiquity in almost all countries of the world. In most forms, the puppet is manipulated either directly by hand, or by rods, strings or wires. Shadows of puppets are also sometimes used in a performance.
Perhaps the most advanced form of puppetry is Bunraku Puppetry. This form was originally developed at the end of the sixteenth century in Japan, and later took its name from Uemura Bunrakuken, a famous Japanese promoter in the early nineteenth century. Bunraku puppetry requires teams of three to four puppeteers to stand behind each puppet and move the arms, legs, mouth and body using rods and the puppeteer's hands. Normally, there is a chief manipulator and two or more assistants to manipulate movement of the puppet. Since three or four people handle the different parts of the puppet, life-like motion cannot be achieved without precision timing among the manipulators. For all motions, there are detailed rules and forms to be followed. No manipulator is allowed to act on their own.
In Japan, when operating this type of puppet on stage, the manipulators, as a rule, wear black gowns and black hoods. This signifies that the puppet is the main performer with the manipulator remaining behind the scenes and/or blended into the background. In the Japanese theatrical tradition, black costumes represent the invisible or nothingness.
In the present-day video and film environment, puppetry has and continues to survive and thrive. More specifically, notwithstanding the advances made in animation, puppetry continues to provide more life-like and realistic action imagery. This is achieved, in part, by the skill of the puppeteers, advanced camera techniques, the digital processing of the real images and the compositing of the real and virtual images in the finished video/film sequences. One of the filming techniques that has permitted the advancement of this art form, and its adaptation to modern imaging media, is known in the film industry as the “blue screen or key-color process”. More specifically, it is common practice to combine two or more images into a single scene. This technique of combining images is primarily achieved through use of a key-color process in which one image is photographed against a solid key-color background, (such as blue, green or grey) and the second image is substituted in place of that key-color background. It is also known that the background can be various other colors, and that the substitution can be made electronically, or through optical photographic techniques. This process is also known as the “keying” or the “Chroma key” process.
For example, it is commonplace to film an image of an announcer with a live camera (e.g. live image) in front of a blue screen, as a foreground image. Subsequently, a background image is generated in real time as a result of graphics processing performed by a high speed computer, and is super-imposed on the foreground image. The super-imposed portion of the background image and the foreground image is blanked out by the keying process and a composite image is obtained by fitting an object's image portion of the foreground image into the blank portion of the background image.
Although there are many advantages to using the standard key-color process, there are also several disadvantages. For example, the key-color process is generally an iterative process in which the end product, or combined file or video, is composited or “married in post” and is not viewable for evaluation until the entire process has been completed. As a result, film producers frequently view the end product and require changes to either the foreground or background portions, requiring that the entire sequence be “reshot”. Furthermore, because the process is post rendered in real-time, it is difficult to perform actual interaction between a moving puppet, for example, and the puppet's environment. The normal cycle for “blue screen” film production can require several iterations of this process.
The following patents are representative of the relevant art and thus summarized below, to the extent believed related to the subject matter of the instant invention.
U.S. Pat. No. 4,689,683 (to Efron., issued Aug. 25, 1987) discloses an image compositing system that permits real-time composition and editing of the composite image, specifically, a real image filmed against a blue screen background with a background image or fill image. An example of such a system is where the background information is provided by filming a miniature model rather than a life-size scene. According to Efron, the actors carry forward their activities before a blue screen and the background information is supplied by a separate camera filming the miniature model. The eventual composite is formed by scaling the respective background and foreground inputs to provide appropriate proportions between the foreground objects and the background objects. In the Efron system, the motion of the camera filming the foreground objects or actors performances must be duplicated by the camera filming the background scene information. That is to say if an actor in the foreground filming moves to the right and the camera moves with the actor to display that motion, there must be a corresponding motion of the camera filming the miniature model in the example given. It is the function of camera filming the foreground image to provide this coordinated or slaved motion of the secondary camera.
The compositing of the an action and background image in real-time permits the television or film producer to display and view the scene as it is occurs. In addition, the image processing enhancements provided by Efron, permit the television or film producer to view the resultant composited scene as it is actually occurring and, as appropriate, modify, enhance or embellish that image information for compositing into a final completed scene depiction. The importance of this advantage cannot be over emphasized to real-time editing of the composite image. Moreover, the ability to evaluate the composited scene in real time completely eliminates any iterative process under which the previous cinematography blue screen processes functioned and the concomitant delay and expenses.
U.S. Pat. No. 5,479,597 (to Fellous, issued Dec. 26, 1995) discloses a virtual camera having a parametric model of a real camera forming part of a filming system. According to Fellous, the synthetic (virtual) images are obtained through a graphics computer equipped with image synthesizing software; and, a dynamic coupling between the two cameras, real and virtual, securing perfect coherence between each real image and each virtual image of a series of images. This dynamic coupling permits the control of the virtual camera by the real camera and vice versa. The Fellous' virtual camera, thus, permits a real image to be combined with a virtual set, thereby the creation of a composite image of life-like quality with relative modest facilities and expenses.
U.S. Pat. No. 5,764,306 (to Steffano, issued Jun. 9, 1998) discloses a method that allows the real-time replacement of the designated background portion of an incoming video signal with an alternate background. The Steffano method utilizes the actual background image for reference and as the basis for determining the background and foreground elements within the image, with the end result being comparable to traditional blue-screen processes, (such as in the Chroma-key and Ultimatte technology), but requires only a personal computer, video camera and the software. In Steffano method, the reference background image can be any reasonably static scene with a sufficient and stable light source captured by the camera. The video data stream is then modified in real-time by comparisons against the reference background image and is then passed onto its original destination. Multiple signal-noise processing algorithms are applied in real-time against the signal to achieve a visually acceptable matte.
U.S. Pat. No. 5,949,433 (to Klotz, issued Sep. 7, 1999) discloses a method for processing image data, wherein real image data generated by a camera is combined with synthesized image data, comprising the steps of generating camera positional data representing characteristics of said camera, including an indication of zoom control; generating a synthesized image in response to said positional data; and adjusting the perceived focus of said synthesized image in response to zoom control adjustments, so as to effect a focusing difference between a portion of said real image and a portion of said synthesized image. The image processing capability of the Klotz method, thus, allows for the film director to project a virtual image into or out of a scene, in proportion to the objects within the other objects within scene.
U.S. Pat. No. 6,034,740 (to Mitsui, et al., issued Mar. 7, 2000) discloses a simple and inexpensive non-volatile memory storage device having a keying system, which include a recorded image of an object and recorded images of a plurality of the background images, each of which has a corresponding view angle of a view point in a three-dimensional space to be imaged, and a view position of the view point therein. The background image from the plurality of background images stored in the memory device can be selectively read according to the view angle and the view position preliminarily defined in accordance with the image of the object. A Chroma-keying composition is performed between the background image and the image of the object thereby producing a composite image.
According to Mitsui, et al., because his system includes a plurality of background images which are preliminarily stored on a memory device, (for example a simple disk array unit), the Chroma-keying composition of a composite image does not use nor require advanced high-speed (high-performance) graphics processing and high-speed (high-performance) image processing. Consequently, a small computer such as a personal computer having an usual-performance (speed) CPU suffices as a controller for his system configuration. Therefore, Mitsui, et al., reports that both simplification of the system configuration and reduction in cost can be achieved without sophisticated skills and large-scale facilities.
Notwithstanding the advancements in image processing and composite image techniques, the application of such techniques to puppetry has yet to be applied to its full advantage. More specifically, the composting of a real image of different puppets within a given action sequence, presents problems that have heretofore been insoluble. More specifically, the manipulation of a puppet character in the foreground of a virtual studio set by one team of puppeteers, will necessarily result in puppeteer cross of the action puppet character positioned behind it. Thus, the puppeteer manipulation of more than one puppet figure at the same time, on the same virtual studio set, has been severely limited by the very narrow spatial constraints within the virtual studio set, that is by essentially confining such puppets to a parallel plain on the virtual production set. These constraints, thus, prevent realistic/life-like interaction between two or more puppets within a given virtual studio space. Accordingly, there is and remains a continuing need to adapt and utilize virtual studio space more effectively to permit more realistic and life-like interaction of puppets within a given virtual studio, and yet avoid the interference therebetween associated with crossing by one puppet of the other.